319 research outputs found

    De onde surgem os modelos? As origens e expansões Tupi na Amazônia Central

    Get PDF
    This article presents archaeological data for the debate - revisited in the Revista de Antropologia by Franciso Noelli, Eduardo Viveiros de Castro and Greg Urban - on a putative origin of the Tupí languages in the Central Amazon. We present here the preliminary results of the archaeological research we have been undertaking in the area of confluence of the Negro and Solimões rivers which seem not to support the archaeological premises of this model, first presented by Donald Lathrap in 1970.Este artigo apresenta subsídios arqueológicos para o debate - revisitado por Franciso Noelli, Eduardo Viveiros de Castro e Greg Urban nas páginas da Revista de Antropologia - sobre a suposta origem das línguas do tronco Tupí na Amazônia central. Apresentamos aqui os resultados preliminares de nossas pesquisas arqueológicas na área de confluência dos rios Negro e Solimões que levantam restrições às premissas arqueológicas desse modelo, primeiramente apresentadas por Donald Lathrap em 1970

    Historical biogeography of the neotropical Diaptomidae (Crustacea:Copepoda)

    Get PDF
    Introduction: Diaptomid copepods are prevalent throughout continental waters of the Neotropics, yet little is\ud known about their biogeography. In this study we investigate the main biogeographical patterns among the\ud neotropical freshwater diaptomid copepods using Parsimony Analysis of Endemicity (PAE) based on species records\ud within ecoregions. In addition, we assess potential environmental correlates and limits for species richness.\ud Results: PAE was efficient in identifying general areas of endemism. Moreover, only ecoregion area showed a\ud significant correlation with diaptomid species richness, although climatic factors were shown to provide possible\ud upper limits to the species richness in a given ecoregion.\ud Conclusion: The main patterns of endemism in neotropical freshwater diaptomid copepods are highly congruent\ud with other freshwater taxa, suggesting a strong historical signal in determining the distribution of the family in the\ud Neotropics.We would like to thank to Professor Edinaldo Nelson dos Santos Silva (INPA, Brazil) for useful insight during this study. We also thank FAPESP (process 2008/02015-7, 2009/00014-6, 2011/18358-3) for financial support to GPN; and CNPq for financial support to DP (process 141702/2006-0) and MRP (process 304897/2012-4)

    A correlation analysis of Light Microscopy and X-ray MicroCT imaging methods applied to archaeological plant remains’ morphological attributes visualization

    Get PDF
    In this work, several attributes of the internal morphology of drupaceous fruits found in the archaeological site Monte Castelo (Rondonia, Brazil) are analyzed by means of two different imaging methods. The aim is to explore similarities and differences in the visualization and analytical properties of the images obtained via High Resolution Light Microscopy and X-ray micro-computed tomography (X-ray MicroCT) methods. Both provide data about the three-layered pericarp (exo-, meso- and endocarp) of the studied exemplars, defined by cell differentiation, vascularisation, cellular contents, presence of sclerenchyma cells and secretory cavities. However, it is possible to identify a series of differences between the information that can be obtained through each of the methods. These variations are related to the definition of contours and fine details of some characteristics, their spatial distribution, size attributes, optical properties and material preservation. The results obtained from both imaging methods are complementary, contributing to a more exhaustive morphological study of the plant remains. X-ray MicroCT in phase-contrast mode represents a suitable non-destructive analytic technique when sample preservation is required

    Association between serum lactate levels and mortality in patients with cardiogenic shock receiving mechanical circulatory support : a multicenter retrospective cohort study

    Get PDF
    Background: To evaluate the prognostic value of peak serum lactate and lactate clearance at several time points in cardiogenic shock treated with temporary mechanical circulatory support (MCS) using veno-arterial extracorporeal membrane oxygenation (VA-ECMO) or Impella CP®. Methods: Serum lactate and clearance were measured before MCS and at 1 h, 6 h, 12 h, and 24 h post-MCS in 43 patients at four tertiary-care centers in Southern Brazil. Prognostic value was assessed by univariable and multivariable analysis and receiver operating characteristic (ROC) curves for 30-day mortality. Results: VA-ECMO was the most common MCS modality (58%). Serum lactate levels at all time points and lactate clearance after 6 h were associated with mortality on unadjusted and adjusted analyses. Lactate levels were higher in non-survivors at 6 h, 12 h, and 24 h after MCS. Serum lactate >1.55 mmol/L at 24 h was the best single prognostic marker of 30-day mortality [area under the ROC curve=0.81 (0.67–0.94); positive predictive value=86%). Failure to improve serum lactate after 24 h was associated with 100% mortality. Conclusions: Serum lactate was an important prognostic biomarker in cardiogenic shock treated with temporary MCS. Serum lactate and lactate clearance at 24 h were the strongest independent predictors of short-term survival

    Electrocatalytic oxidation of oxalic and oxamic acids in aqueous media at carbon nanotube modified electrodes

    Get PDF
    The electrochemical oxidation of oxalic and oxamic acids on multiwalled carbon nanotubes (CNT) and on monometallic (Pd and Pt) and bimetallic (Pd-Cu, Pt-Cu) catalysts supported on multiwalled carbon nanotubes was investigated using cyclic voltammetry. The electrodes were prepared by dispersion of the catalytic material on Toray carbon (CT) using a Nafion/water solution. The kinetic parameters of the reactions were determined using cyclic voltammetry. Modification of Toray carbon electrode with carbon nanotubes enables the oxidation of oxalic and oxamic acids in the solvent stability region. The highest oxidation current densities were observed for the Pt-Cu/CNT/CT electrode in 0.1 M NaCl. The oxidation potentials for both oxalic and oxamic acids in this case were lower than those observed with the CNT/CT electrode. The prepared electrocatalysts show good mechanical and chemical stability.Support for this work was provided by the project NANO/NTec-CA/0122/2007 financed by Fundacao para a Ciencia e a Tecnologia (FCT), Portugal and FEDER, in the context of Programme COMPETE
    corecore